From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753265AbcKPNM6 convert rfc822-to-8bit (ORCPT ); Wed, 16 Nov 2016 08:12:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51068 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751563AbcKPNM5 (ORCPT ); Wed, 16 Nov 2016 08:12:57 -0500 Message-ID: <1479301975.25611.23.camel@redhat.com> Subject: Re: BUG: 'list_empty(&vgdev->free_vbufs)' is true! From: Gerd Hoffmann To: Jiri Slaby Cc: "Michael S. Tsirkin" , virtualization@lists.linux-foundation.org, Linux kernel mailing list , David Airlie , dri-devel@lists.freedesktop.org Date: Wed, 16 Nov 2016 14:12:55 +0100 In-Reply-To: References: <20161108223153-mutt-send-email-mst@kernel.org> <1478678517.2078.12.camel@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Mime-Version: 1.0 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 16 Nov 2016 13:12:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fr, 2016-11-11 at 17:28 +0100, Jiri Slaby wrote: > On 11/09/2016, 09:01 AM, Gerd Hoffmann wrote: > > On Di, 2016-11-08 at 22:37 +0200, Michael S. Tsirkin wrote: > >> On Mon, Nov 07, 2016 at 09:43:24AM +0100, Jiri Slaby wrote: > >>> Hi, > >>> > >>> I can relatively easily reproduce this bug: > > > > How? > > Run dmesg -w in the qemu window (virtio_gpu) to see a lot of output. > Run pps [1] without exit(0); on e.g. serial console. > Wait a bit. The lot of output causes the BUG. > > [1] https://github.com/jirislaby/collected_sources/blob/master/pps.c Doesn't reproduce here. Running "while true; do dmesg; done" on the virtio-gpu fbcon. Running the pps fork bomb on the serial console. Can watch dmesg printing the kernel messages over and over, until the shell can't spawn dmesg any more due to the fork bomb hitting the process limit. No BUG() triggered. Tried spice, gtk and sdl. Hmm. Any ideas what else might be needed to reproduce it? cheers, Gerd From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: BUG: 'list_empty(&vgdev->free_vbufs)' is true! Date: Wed, 16 Nov 2016 14:12:55 +0100 Message-ID: <1479301975.25611.23.camel@redhat.com> References: <20161108223153-mutt-send-email-mst@kernel.org> <1478678517.2078.12.camel@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jiri Slaby Cc: David Airlie , virtualization@lists.linux-foundation.org, Linux kernel mailing list , dri-devel@lists.freedesktop.org, "Michael S. Tsirkin" List-Id: virtualization@lists.linuxfoundation.org On Fr, 2016-11-11 at 17:28 +0100, Jiri Slaby wrote: > On 11/09/2016, 09:01 AM, Gerd Hoffmann wrote: > > On Di, 2016-11-08 at 22:37 +0200, Michael S. Tsirkin wrote: > >> On Mon, Nov 07, 2016 at 09:43:24AM +0100, Jiri Slaby wrote: > >>> Hi, > >>> > >>> I can relatively easily reproduce this bug: > > > > How? > > Run dmesg -w in the qemu window (virtio_gpu) to see a lot of output. > Run pps [1] without exit(0); on e.g. serial console. > Wait a bit. The lot of output causes the BUG. > > [1] https://github.com/jirislaby/collected_sources/blob/master/pps.c Doesn't reproduce here. Running "while true; do dmesg; done" on the virtio-gpu fbcon. Running the pps fork bomb on the serial console. Can watch dmesg printing the kernel messages over and over, until the shell can't spawn dmesg any more due to the fork bomb hitting the process limit. No BUG() triggered. Tried spice, gtk and sdl. Hmm. Any ideas what else might be needed to reproduce it? cheers, Gerd